Removable tooth pavement mixer wheel construction



April 1968 5v A. PETERSEN 3,375,764

REMOVABLE TOOTH PAVEMENT MIXER WHEEL CONSTRUCTION Filed Oct. 21, 1965 3 Sheets-Sheet l I60 33 M k [2 INVENTOR. Gerald A. Petersen BY W 42g April 2, 1968 A. PETERSEN 3,375,764

REMOVABLE TOOTH PAVEMENT MIXER WHEEL CONSTRUCTION Filed on. 21, 1965 5 Sheets-Sheet 2 INVENTOR. Gerald A. Petersen April 2, 1968 A. PETERSEN REMOVABLE TOOTH PAVEMENT MIXER WHEEL CONSTRUCTION 3 Sheets-Sheet 3' Filed Oct. 21, 1965 INVENTOR. Gerald A. Petersen United States Patent O 3,375,764 REMOVABLE TOOTH PAVEMENT MIXER WHEEL CONSTRUCTION Gerald A. Petersen, Sunnyvale, Calif., assignor of one-half to Anita E. Petersen, Saratoga, Calif. Filed Oct. 21, 1965, Ser. No. 500,058 8 Claims. (Cl. 94-40) ABSTRACT OF THE DISCLOSURE teeth are parallel.

This invention relates to a new and improved removable tooth pavement mixer wheel construction. A commercially available machine used in mixing the bed for pavement employs a plurality of parallel wheels rotatable about a transverse horizontal axis. The axis of the wheel may be adjusted relative to the ground to dig the underly ing ground to a desired depth, carry the excavated material around to a mixing chamber surrounding the upper parts of the wheels, pulverize and thoroughly mix the roadbed material with or without chemical additives and replace the mixed material in a position behind where it had been excavated. Thereafter, other equipment compacts the mixture preparatory to laying the pavement.

It has been customary to mount sockets on the periphery of each wheel to receive replaceable teeth which bear most of the abrasion of the digging action. Facility in installing and removing the replaceable teeth is one of the problems with which the present invention is concerned. A further problem in conventional machines arises out of the fact that the teeth are set in the wheel at angles with respect to each other so that each wheel cuts a relatively wide swath as the machine advances and the sockets for those teeth which are slanted outwardly with respect to the plane of rotation of the wheel tend to wear away very rapidly. Although replacement of the teeth is an accepted cost of maintenance of the machine, replacement or repair of the sockets for the teeth is especially time-consuming and expensive and results in considerable down-time for the machine. The present invention comprises an importat improvement in the aspects heretofore described.

One of the features of the invention is the provision of a wheel construction consisting of two cast halves, which are bolted together, of particularly rugged although relatively light weight construction, each half providing pockets for three replaceable tooth holders, each tooth holder in turn receiving one identical tooth. One of the tooth holders is disposed to hold the tooth which it carries centered relative to the plane of rotation of the wheel while one of the other pockets is shaped to carry the tooth holders positioned so that its tooth is on one side of the plane of rotation and the third pocket is disposed so that the tooth carried by its holder is on the opposite side of the wheel. Since the cutting edges of the teeth are relatively wide, the width of the three teeth cuts a swath of considerable width.

Another feature of the invention is the fact that the tooth holders and teeth used in all three pockets are essentially identical making for interchangeability of parts and yet a particular holder and tooth may be so located in the wheel as to be disposed either on the center or to either side thereof.

A particular feature of the invention is the fact that the 3,375,7 64 Patented Apr. 2, 1968 tooth holder is positioned directly in line with the blade of the tooth performing the cutting action and thus the, tooth absorbs the abrasive action of the ground being dug rather than the holder, and the wear of the holder is considerably reduced over conventional machines of this type.

A still further feature of the invention is the fact that the tooth holders are held securely in pockets in such manner that the holders are not easily fractured or worn nor do they tend to come out of alignment even with prolonged wear. On the other hand, the replaceable teeth are so located that a workman can conveniently change the teeth rapidly.

A still further feature of the invention is the fact that the pockets for the tooth holder have tapered walls and the tooth holders have tapered bosses which wedge into the pockets very securely and when bolted therein do not work loose despite rapid rotation of the wheels and high energy applied. On the other hand, when it is necessary to replace the holders, this can be accomplished with a minimum of time and effort required.

An optional feature of the invention is the incorporation of heavy weights on the tooth holders behind the teeth. The mass of such weights improves the action of the wheel and permits the teeth to break up pavement.

Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings. in which similar characters of reference represent corresponding parts in each of the several views.

In the drawings:

FIG. 1 is a schematic side elevational view through a portion of the pavement machine With which the present invention is used showing the rotor in elevated position.

FIG. 2 is an enlarged side elevational view of a wheel in accordance with this invention.

FIG. 3 is a top plan view as viewed along the line 3-3 of FIG. 2, partly broken away.

FIG. 4 is a view similar to FIG. 3 prior to installation of tooth holders.

FIG. 5 is a fragmentary enlarged sectional view taken substantially along the line 55 of FIG. 2.

FIG. 5A is a view similar to FIG. 5, taken along line 5A5A of FIG. 2.

FIG. 6 is a sectional view through a holder substantially along line 6-6 of FIG. 12.

FIG. 7 is an enlarged sectional view taken substantially along line 7-7 of FIG. 6.

FIG. 8 is a front elevation of the structure of FIG. 2.

The pavement machine shown schematically and partially in FIG. 1 has an arcuate downward facing casing 11 which rides over ground on which a pavement is to be laid inthe direction of the arrow to the left in FIG. 1. There is a rotatable shaft 12 here shown as square in cross section disposed centrally of the casing which rotates counterclockwise as viewed in FIG. 1 as the machine advances. The elevation of shaft 12 relative to the ground is adjustable to control the depth of cut. In FIG. 1, shaft 12 is in elevated position. As the machine revolves and advances, soil is excavated, carried up around the casing 11 where it is pulverized and thoroughly mixed so that the various layers of material are made substantially homogenous and chemical additives may be incorporated in the mix and then deposited out through the rear end 13 in a uniform depth. Other machinery is used to compact the mixed dirt preparatory to the actual paving operation. Shaft 12 carries a plurality of rotor wheels 14 with which the present invention is concerned spaced across the width of the machine and carrying teeth 16 disposed in a pattern so that the swath of each wheel overlaps the adjacent wheels and the entire width of the roadway being processed is dug.

Rotor 14 is composed of two halves 14a and 14b meeting along a plane through diagonals of shaft 12, the two halves being bolted together by means of bolts and nuts 17, 18 through abutting flanges 19. When the bolts 16 are tightened, the two halves 14a and 14b comprise a rigid unitary wheel for the purpose intended. Each half, in addition to flanges 19, has further reinforcements. Thus surrounding shaft 12 are angularly disposed inner reinforcements 21. Radially projecting ribs 22 extend from members 21 to the three pocket forming reinforcements 23 for the three tooth holders used on each Wheel half. Two of the radial reinforcements 22 are disposed 30 from flanges 19 and the central radial rib 22 is disposed 60 from the other two ribs 22. Arcuate reinforcements 24, 24a interconnect pocket forming reinforcements 23 and flanges 19. Peripheral reinforcements 26 disposed in a hexagonal pattern comprise the rim of each wheel half. Accordingly, each wheel half is rigid, exceptionally rugged and yet light in weight, being reinforced against the stresses ordinarily encountered in the severe operating conditions in which pavement mixing machines operate.

Each pocket forming reinforcement 23 defines the shape of a pocket for a tooth holder 31 which is next described. The three pockets formed in each half wheel 14a are slightly different in configuration as will later be described, but the tooth holders 31 (and also the teeth 16 which are held therein) are essentially the same. Each tooth holder 31 has a radially disposed portion 32 and a peripheral portion 33 disposed at an angle of approximately 67 with respect to portion 32. Inner portion 32 is formed of a straight relatively narrow connector 34 having at its inner end on either side a boss 36 which diminishes in diameter outwardly from either side of the connecting portion 34. A second or outer boss 37 which also converges outwardly is formed on either side adjacent the periphery of each wheel half 14a. Holes 38 for plow bolts (having countersunk extremities 39) are formed centrally with respect to bosses 36, 37.

Tooth holder 33 is attached to the other end of radial portion 32. Socket forming portion 33 has outer and inner flanges 56, 57 interconnected by web 58 so that it is H- shaped in cross section. Tooth 16 is formed with a pair of prongs 39 at its proximal end as is explained in Petersen Patent 2,968,880. As is also explained in said patent, a hole (not shown) may be formed in web 58 to receive a short piece of resilient material 42 such as natural or synthetic rubber which is compressed within grooves 41 in the walls of web 38 and the sides of the prongs 39 to restrain unintentional withdrawal of tooth 16 from the socket forming member 33. In use, tooth 16 is driven back into socket forming member 33, bending the rubber insert 42 backwardly into the grooves 41 and causing the compression thereof heretofore mentioned. When it is necessary to remove the tooth, it can be driven out of the socket forming member 33 by tools forming no part of the present invention. Thus the teeth 16 are held in place securely but can be rapidly changed when required.

Each tooth 16 has a transverse cutting edge 43. As "best shown in FIG. 8, it is desired that the center tooth 16a of each of the three teeth secured by particular half wheel 14a, be centrally disposed, that one tooth 16b be disposed to the left of tooth 16a and only partially overlapping the same and that the third tooth 16c be oppositely disposed from tooth 16a relative to tooth 16b. A feature of the present invention is that the tooth holders 31 for all three teeth are parallel to each other although staggered relative to a central plane through the half wheel 14a. This arrangement insures that each tooth holder and each tooth will be parallel to the plane of rotation of the wheel and excessive wear of the side edges, which is one of the chief problems of maintenance of prior machines of this general type, will be largely eliminated. The cut ting edge 43 of each tooth cuts ahead of its holder with a swath as wide as the socket forming portion 33 and hence excessive abrasion of portion 3 is avoided.

An important means whereby the foregoing result is accomplished resides in the construction of the three pockets 23. The central pocket 23a is shown in FIG. 5A. The central web 45 of the wheel half 14a is shown in said figure. The pocket forming reinforcement 23a has a tapered walled pocket 46a which is complementary to the taper of boss 37 (or boss 36) so that the bosses wedge firmly in their pockets. A web 47 limits inward movement of the boss 37. Plow bolt 48 fits through hole 38 and passes through a hole in web 47 and is held in position by nut 51, which may be a stop nut. A circular rim 49 on the opposite side of web 47 from pocket 46 protects the end of the bolt 48 and nut 51 from excessive wear. The central pocket 46a shown in FIG. 5A is deeper than the corresponding pocket 46b shown in FIG. 5. Since the holders 31 are all identical, the depth of pocket 46a of FIG. 5A insures that the holder 3111 will be centrally disposed relative to web 45. However, the depth of pocket 46b shown in FIG. 5 is of lesser depth than in FIG. 5A and hence holder 31b is held displaced outwardly relative to web 45 to accomplish the staggering of the teeth heretofore mentioned. The pocket 460 for holder 310 is similar to that shown in FIG. 5 but disposed on the opposite side of web 45. Since the tapers on both sides of holder 31 are the same, the holders are interchangeable for either the central pocket 46a or either side pocket 46b, 46c. Pockets 46a and 461) are on the same side of web 45 while pocket 460 is on the opposite side thereof.

As an optional feature, the mass of member 33 may be considerably increased over that herein illustrated. Such mass causes the teeth to function as a hammer mill and break up quite heavy formations, such as pavement. The location of mass near the periphery of the rotor functions further as a flywheel. This feature is shown schematically in the lower right-hand corner of FIG. 2, as indicated by dot-and-dash lines and reference numeral 40.

Although the foregoing invention has been described in some detail, by way of illustration and example for purposes of clarity and understanding, it is understood that certain changes and modifications may be practiced within the spirit of the invention and scope of the appended claims.

What is claimed is:

1. A rotor construction comprising a central portion apertured to receive a shaft, a plurality of pockets formed spaced around the periphery of said central portion, detachable tooth supports, each partially received in one said pocket and projecting outward of said periphery and formed with a tooth holder at its outer end shaped to receive the proximal end of a tooth, and means detachably securing said tooth supports in said pockets, at least some of said pockets being of different depths and facing opposite sides of said rotor, said supports being staggered relative to a central plane perpendicular to the axis of rotation of said rotor and disposed centrally relative to said axis, whereby at least one tooth holder is located on said central plane and at least one tooth holder is located adjacent but spaced in an axial direction from said plane.

2. A rotor construction according to claim 1, in which said tooth holder is oblique to a radial line but is directed to hold a tooth perpendicular to the axis of rotation of said shaft.

3. A rotor according to claim 1, in which another said holder is located spaced from said central plane in an axial direction opposite said last mentioned plane.

4. A rotor according to claim 1, in which said pocket extends substantially radially in a pocket forming boss in said rotor, the first mentioned of said pockets extending from one side of said rotor to a depth beyond said central plane, the second mentioned of said pockets terminating remote from said central plane.

5. A rotor according to claim 1, in which each said tooth support has a first knob at its inner end, a second knob intermediate its length and a connecting portion between said knobs, said pocket shaped complementary to said knobs and connecting portions and which further comprises fastening means through said knobs to secure said supports to said rotor.

6. A rotor according to claim 5, in which the peripheries of said knobs are outward diverging to wedge in ,said pocket.

7. A rotor according to claim 6, in which opposite peripheries of said knobs are oppositely outwardly diverging, whereby said tooth supports are interchangeable for opposite sides of said rotor.

8. A rotor according to claim 1, in which mass is in- References Cited UNITED STATES PATENTS 1,661,692 3/1928 Everist. 1,732,883 10/1929 Fagan. 2,657,620 11/1953 Meeks 172l23 X 2,968,880 1/1961 Petersen 37-142 3,203,488 8/1965 Eastwood 37-142 JACOB L. NACKENOFF, Primary Examiner. 

